Seattle-based Mirador Biomedical is trying to sell hospitals a little digital device for about $35 apiece, in hopes of preventing a rare and disastrous thing from happening to patients. Now the company has gathered some data that it hopes will prove it’s worth the money. Mirador’s device is a digital pressure sensor that’s supposed to help medical professionals tell whether they are about to insert a thick central line catheter into an artery instead of a vein (a classic hospital screw-up that can lead to an emergency hemorrhage, stroke, or death). Researchers working with Mirador wanted to know if the device could help prevent these errors from happening, and see whether the tool can save the healthcare system more money than it costs.